Put the stock in a saucepan and turn it to medium high. Add the diced tomatoes, the stems from the cilantro, the garlic, and the chiles. Let simmer 10-15 minutes.

Meanwhile, heat the oil in a wide skillet (preferably an ovenproof one, otherwise you're going to have to move this stuff into something ovenproof later) over medium heat. Add the noodles and saute until browned. Puree the stuff from the saucepan and strain it. Pour most of it into the skillet with the noodles. Simmer until most of the liquid has been absorbed, about 10 minutes. If the noodles aren't soft yet and they're getting dry, add a bit more stock.

Meanwhile, preheat your broiler.If you don't have this stuff in an ovenproof skillet, now is the time to move it to a short, wide dish that can stand up to the broiler. If you do, just keep going. Sprinkle the cheeses over top and broil until the cheese has melted. Remove from the oven. Stir your sour cream with a fork and drizzle it over top, then sprinkle the cilantro over top. Serve.